In the mouth a natural equilibrium exists between hydroxyapatitie being dissolved from the enamel of teeth, on the one hand, and hydroxyapatitie being formed on or in the teeth from substances occurring naturally in the saliva, on the other hand. When the equilibrium is such that the hydroxyapatite is dissolved, a cariogenic condition arises which is referred to as demineralization. If the equilibrium is such that hydroxyapatite is being formed in demineralized enamel, this is referred to as remineralization. By remineralization, pre-existing tooth decay and caries can be reduced or eliminated by natural means.
It has long been known that fluoride-providing compounds, even in low concentrations, are a safe and effective means for the promotion of the remineralization process. In addition the prior art, specifically WO 98/40406, published Sep. 17, 1998, The University of Melbourne and The Victorian Dairy Industry Authority, Reynolds, teaches phosphopeptides (casein derived or otherwise) containing the cluster sequence motif Ser(P)-Ser(P)-Ser(P)-Glu-Glu- (herein referred to as “PP”) can stabilize their own weight in amorphous calcium phosphate (herein referred to as “ACP”). The amorphous phases stabilized by the phosphopeptides are taught as an excellent delivery vehicle to co-localize Ca, F, and phosphate at the tooth surface in a slow-release amorphous form producing good anticaries efficacy.
Despite the above known prior art and technologies for treatment of caries, the prior art has not fully appreciated or solved problems associated with combining PP-ACP with other ingredients to form oral care, composition such as dentifrices or mouthrinses. In particular, certain incompatibilities may arise with respect to the addition of PP-ACP with other components such as fluoride, rendering reduced fluoride ions levels within the oral care formulation. The present invention minimizes this instability of the combination of fluoride ions and PP-ACP through the addition of a calcium chelator at specific levels.